The most common method of producing optoelectronic components, e.g., white light-emitting diodes, is the use of a blue light-emitting diode (LED) with radiation in the range of 400 to 470 nm in combination with one or more luminescent phosphors. The phosphor absorbs at least partially a fraction of the blue light and emits light in the range of 500 to 700 nm in a process commonly referred to as down conversion.
The combination of the down-converted light and the blue radiation from the LED or semiconductor chip provides a full spectrum white light. It is known that the energy of the emitted white light is less than the electrical energy supplied to the LED due to a number of factors. There is thus a need to address two types of energy loss, in particular the loss of blue light on the interface between the chip and the encapsulating matrix and the loss of multi-wavelength light that is passing through the phosphor filled conversion material. The first loss occurs due to a total internal reflection on the interface between the LED and encapsulation matrix material which is proportional to the ratio of the refractive index of the LED material, (for example, 2.44 for indium gallium nitride) and that of the phosphor matrix material, which is from 1.4 to 1.55 for most of the currently used commercial polymeric matrix materials. The second loss occurs due to the loss of light scattered by the phosphor particles. That scattering is proportional to the ratio of the refractive index of the phosphor particles, for example, 1.8 for YAG-type phosphor) to that of the matrix material. It is easy to see that increasing the refractive index of the matrix material is expected to reduce both types of light losses and result in a higher efficiency of the phosphor-converting LED products.
It could therefore be helpful to provide an optoelectronic component having a conversion element, wherein in particular the conversion element has a high refractive index.